Regression test for bug 226033399.

This CL adds a test to verify that keyboard remains visible
when a notification comes.

The test is skipped on the following cases, in case the
device-under-test has a non-standard notification UI.
(1) on TV, Automotive, and Wear devices.
(2) on small-screen devices.

Bug: 226033399
Bug: 230027493
Test: atest CtsInputMethodTestCases:KeyboardVisibilityControlTest
Change-Id: I23c6449ec2ec76079c55948b8adff7828c095499